Prebiotic vs Probiotic: This is What You Need to Know

You’ve most likely heard of probiotics before: You know, those friendly little gut bacteria that keep your digestive system squeaky clean and help you digest the foods you eat.

But we don’t hear much about prebiotics, even though they’re just as important.

In fact, without prebiotics, the probiotics in your gut would be out of luck. That’s because prebiotics feed them the nutrients they need to do grow and do their job.

And although they sound the same, prebiotics and probiotics are entirely different from each other, each contributing their own unique health benefits to your gut.

What are Prebiotics?

Prebiotics are a type of nondigestible fiber found mostly in plants and other carbohydrates.

They contain the nutrients that nourish the existing good bacteria – or probiotics – in your gut. Prebiotics have also been named superfoods or “fertilizers,” as they allow the beneficial bacteria to grow.

Since they’re found in many plant fibers, prebiotics are easy to obtain from your diet if you eat a wide variety of plant-based foods.

Prebiotics can also be found in higher concentrations in nutritional supplements at your local health food store, especially fiber supplements or the supplements used in “bowel cleansing” protocols.

The most common varieties of prebiotics are fructooligosaccharides (also known as fructans) and galacto-oligosaccharides.

Inulin is an example of an fructooligosaccharide that acts as a prebiotic, and it’s found in many fruits and vegetables. Inulin is also found in high concentrations in chicory root, which explains why chicory root is one of the most common ingredients in supplements for improved digestive health.

The importance of obtaining prebiotics from our diet cannot be understated – and that’s why prebiotic-rich foods are on my list of ultimate superfoods.

Without prebiotics, the good bacteria in our gut wouldn’t be able to grow or thrive, which means our health would become severely depleted.

Prebiotics vs. Probiotics

When comparing prebiotics vs. probiotics, there are a few key differences.

Also, probiotics are beneficial bacteria that exist in your gut, while prebiotics act as food for probiotics to grow.

Probiotics are considered living bacteria that help digest the foods you eat, while prebiotics are considered nutrients.

When comparing probiotics and prebiotics in supplement form, probiotics aren’t always able to survive the harsh, acidic temperatures of stomach acid – but prebiotics are, which might make them more helpful to repopulate the body’s stores of good bacteria than an actual probiotic supplement.

What Is the Role of Prebiotics in the Gut?

Since prebiotics allow probiotics to grow, they serve as a critical nutrient in our diets to help keep our digestive systems clean and “well-oiled.”

If you’ve read any of my previous blog posts about gut health (here, here, and here), you may have already heard me explain that all health and disease begins in the gut.

Approximately 80 percent of your immune system is located in your gut, which suggests how important it is to keep it functioning optimally by having a healthy ratio of probiotics, or friendly bacteria, in your system (1).

Since the condition of your gut largely impacts your overall state of health, you can see the importance of the relationship between prebiotics and probiotics, and how they work together to keep your entire body in good health.

And while it’s ideal to have plenty of good bacteria in your system, it should also be noted that a healthy body will always contain small amounts of bad bacteria, too.

This isn’t a bad thing: our bodies require both types of bacteria in a specific ratio for optimal health. However, it’s more common today for bad bacteria to outweigh the good bacteria, also known as a condition called dysbiosis.

Dysbiosis has been linked to diets high in refined sugar, frequent antibiotic use, low fiber, and chronic stress (2).

Therefore, prebiotics serve as the nutrition required for good bacteria to grow, and prevent conditions such as dysbiosis from occurring.

Prebiotics may also help improve with vitamin and mineral absorption – especially vitamin B and calcium, since both nutrients are absorbed in the gut (3).

Prebiotics for Digestive Health

Since prebiotics nourish the already existing good bacteria in your system, it makes sense to say they’re a fundamental nutrient to digestive health.

While more research is needed on the specific benefits of prebiotics to digestive health, current research has proven that prebiotics help improve the formation of bowel movements (which may help relieve constipation), stimulate microflora (or probiotic) production, enhance mineral absorption and even lower triglycerides (4) .

These health benefits suggest that prebiotics may also contribute to relieving symptoms of irritable bowel syndrome (IBS), such as bloating and diarrhea.

How to Get Prebiotics Naturally

You can get more prebiotics in your diet by increasing your intake of fibrous, prebiotic-containing foods.

Here are the top foods known to contain the highest concentrations of prebiotic-rich fructans or galacto-oligosaccharides:

Chicory root

Jerusalem artichoke

Dandelion greens

Onion

Asparagus

Leeks

Banana

Garlic

Prebiotic supplements

Since cooked leeks, asparagus and onion can be difficult to digest in their raw form, I do recommend eating them lightly steamed. However, you will receive fiber from both the raw and cooked forms, which is where the prebiotics are found.

Prebiotic supplements will typically contain several different types of fiber and prebiotics, such as chia seeds and flax, as well as chicory root.

Side Effects of Prebiotics

Although it’s clear that prebiotics are necessary for optimal gut health, prebiotics have been known to aggravate those who already have existing digestive conditions, such as SIBO (small intestinal bacterial overgrowth).

In some cases, prebiotics can help eliminate digestive symptoms such as gas and bloating, but in some people, the symptoms can worsen with increased fiber.

Prebiotics can aggravate existing digestive symptoms because once the digestive process starts and the friendly bacteria begin to break down their indigestible fiber, gas is naturally produced.

Those with relentless digestive symptoms are often advised to follow a low FODMAP diet by a naturopathic doctor or holistic healthcare practitioner.

Why does this matter? A low FODMAP diet refers to eliminating specific classes of nutrients that are known to aggravate digestive symptoms.

FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Basically, these are all indigestible sugar molecules, but you may recognize that they are also prebiotics.

Another reason prebiotics can aggravate digestive symptoms is because the carbohydrates they’re found in ferment in the digestive process.

This fermentation is natural process and isn’t harmful to someone who has a healthy digestive system, as the undigested fiber moves through the colon.

However, in those with weakened digestive systems, the fiber is slower to move through the digestive tract and can ferment in the colon. This can promote the growth of bad bacteria, and symptoms such as bloating and gas.

While there can be some undesirable effects of having too many prebiotics in your diet (that is, if you already experience digestive symptoms), it can help to start with small amounts of prebiotics each day. For example, you may choose to begin adding more prebiotics to your diet simply by having one banana each day, and gradually increase your intake from there.

Since it can be hard to know immediately if prebiotics will improve or aggravate your existing health symptoms, keeping a food and symptom journal can help provide insight.

Adding prebiotics to your diet may initially cause your symptoms to become more noticeable, but may also help symptoms improve after a week or two.

If you’re transitioning from a highly processed diet to a nutrient-rich, high-fiber diet, you will also likely notice initial digestive symptoms such as gas and bloating as your body gets used to the extra fiber (since processed foods contain little to none).

Prebiotics Make Your Gut Happy

For the average healthy person, prebiotics are an entirely safe nutrient to add to your diet that will help keep your gut in sparkling condition.

Now that you understand how prebiotics work in the body, you may also be interested in learning more about what probiotics can do for you. I’ve written an entire post about the pros and cons of probiotics and why you might (or might not) want to include them in your diet.